Electromechanical differential governor



May. 15, 1923.

R. B. GOLDSCHMIDT ET AL ELEGTROMECHANIQAL DIFFERENTIAL GOVERNOR Find may 24 1920 Patented May 15, 1923.

ROBERT B. GOLDSCHMIDT AND RAYMOND BRAILLARD, OF PARIS, FRANCE.

ELECTBOMECHANICAL DIFFERENTIAL GOVERNOR.

AppIication filed May 24,

To all whom it may concern:

Be it known that we, ROBERT BENEDICT GoLDscrrMiDr, a subject of the King of Belgium, residing at Paris, France, and RAY- MOND BRAILLARD, a citizen of the French Re- "public, residing at Paris, France, have invented a new and useful Electromechanical Difl'erential Governor (for which we have filed an application in Belgium, May 22, 1919), of which the following is a specification.

The object of the invention is to provide an improved mechanism of this kind having the following characteristics:

1. Direct comparison of thespeed of the machine to be controlled with a pendulum dividing the time into intervals practically equal.

2. The governor acts continuously as long as the speed of the machine to be controlled is different from the normal speed.

3. The rate of action of the governor is proportional to the speed variation.

In the accompanying drawing Fig. 1 is a diagrammatic elevation of a speed governor constructed and arranged in accordance with my invention.

Fig. 2 is a detail elevation of the drum 2, shaft 10, and their connection.

Fig. 3 is a detail diagrammatic elevation of the contact apparatus.

Fig. 4: is a detail view of controlling means for the sleeve 11 and pinion 15.

Let 1 be the machine, in regard to which the speed must be maintained as near as possible to N revolutions per minute. It acts on a drum 2 turning at the same speed. (See Fig. 1.)

A drum 3 turns independently of drum 2, drum 3 being driven by a motor 4:, the speed of which is maintained constant and equal to N revolutions per minute, by means of a pendulum 5.

The device for synchronizing the motor 4: by the pendulum 5 is known and has been worked out under various forms, for example by an electric clock movement.

The drum 2 carries on it's circumference two series of metallic contacts, 6, 6, 6, and 7, 7, 7 insulated from each other and connected, respectively, by conductors to two insulated rings 8 and 9, mounted on the shaft.

The drum 3 carries on its circumference a shaft 10, parallel to the elements of the cylinder and turning with the drum 3.

19%. Serial No. 383,920.

On this shaft 10 is fixed a sleeve 11 possessing two contact brushes 12 and 13, which rest on the contacts 6 and 7 all being mounted so that only one at most of the contact brushes can enter in contact with the surface of the drum 2.

Fig. shows the device worked out for this purpose: according to whether the sleeve 10 turns to the right or to the left, the contact brush 13 will come in contact with the contacts 7, or the contact brush 12 will come in contact \Vlurl the contacts 6. Tire contact brushes 12 and 13 are in addition connected by a conductor to a ring 14: insulated electrically and mounted on the shaft of drum 3.

On the sleeve 11, a small pinion with fine teeth 15 is mounted loosely in such way that on one hand the friction is sufficient to engage the sleeve 11 and rock the contact brushes 12 and 13 to left and to right when a force is exerted on the teeth of the pinion, and on the other hand the pinion turns freely on the sleeve 11 whenone of the contact brushes is in contact with the drum 2, if the action on the teeth of the pinion is maintained.

The pinion 15 is permanently meshed with a toothed gear 16 carried by the drum 2 and turning with it. The pinion 15 and the sleeve 11 may rotate freely upon the shaft 10, an elastic washer R of any suitable material being interposed between 11 and 15. This elastic washer is secured to the sleeve 11 by any suitable means, and rests against the pinion 15. The elasticity of the washer is such that, on the one hand, the friction is suiiicient to move the sleeve 11 and the contact brushes 12 and 13 to the left or to the right, if an effort is exerted upon the teeth of the pinion, and, on the other hand, the pinion rotates freely upon the shaft lO-when one of the brushes is in contact with the drum 2, if the action of the pinion is main tained.

The ring 1ais connected by a ring and a conductor to one of the poles of a source of current 17.

The two rings 8 and 9 are connected respectively to two electro-magnets 18 and 19, the other poles of these magnets being connected by a common connection to the second pole of the source 17.

It is at o co seen that according to whether the contact brush 12 or 13 has turned against the drum, current from the source will be sent through the windings of the magnet 18 or the magnet 19, when the contact brush touches one of the contacts 6 or 7.

These two magnets are parallel and close together. An armature 20, able to turn about its pivot, and brought to a position of equilibrium by two springs 21 and 22, will be attracted, in case of action by one or other of the magnets.

This armature carries two escapeinent levers 23 and 24 which can turn, in one direction or the other, a wheel 25 with two sets of teeth out in opposite directions and corresponding to each of the levers. When the vane is attracted by the magnet 19, the lever 24 engages and causes the wheel 25 to turn to the right. If the vane is attracted by the magnet 18, the Wheel 25 will advance to the left one division (Fig. 3).

On the shaft of the wheel 25 is mounted the control apparatus 26 of the machine 1, rheostat, steam throttle valve, etc., which will increase or diminish, according to the direction of rotation of the wheel 25, the arrival of the fluid supplying the machine 1.

It is easy enough to understand the action of the governor.

If the machine 1 turns at the normal speed of N revolutions per minute, the two drums 2 and 3 will not possess any relative motion in relation to each other.

Three cases may then present themselves: either the sleeve 11 is in its middle position, when the contact brushes 12 and 13 do not bear on the surface of the drum and the armature 20 is in its position of equilibrium; or one of the contact brushes is turned down and bears on the surface of the drum between two contacts, the armature 20 still remaining in its position of equilibrium; or else one of the contact brushes bears on one of the contacts, the current passing through the winding of the corresponding magnet, the armature is attracted, one of the levers 23 or 24 is engaged with the teeth of the wheel 25, but this lever remains motionless. In the three cases, the wheel 25 remains motionless and the control apparatus 26 keeps the same position.

If the speed of the machine 1 assumes a rate N, faster or slower than the normal, the shaft 10 will be given a movement, relative to the drum, in one direction or the other, the relative speed being equal to the variation NN in the speed, taken with its proper algebraic sign.

The pinion 15 will turn about the sleeve 11, turning one of the brushes 12 or 13 against the drum, and then will rotate freely when the brush bears on the surface of drum 2.

The depressed brush will then pass successively over the different contacts 6 or 7 and at each contact the corresponding magnet will attract the armature 20 which will cause the wheel to rotate each time in a suitable direction and will change the position of the control apparatus 26.

It is at once seen that the action of the governor will be maintained as lon as there is a difference in the speed N no matter how small, and that the rate of action of the governor will always be proportional to this variation in speed. The governor is therefore perfectly differential, in the sense that its action is a function not of the total speed N but of the variation in speed NN.

In consequence, it is strictly dead-beat, in the sense that its action diminishes progressively as the machine returns to normal speed.

The characteristics of the apparatus: di

ameter of the drums, number of contacts. 6, 7, stroke of the brushes 12, 13, etc., may be established in such a way, that the governor will act for a speed variation as small as may be desired.

The above description is given only as an example. It is evident that the arrangement of the accessory apparatus may be modified in many ways, that the system of electromagnets and ratchet may be replaced by any other system performing a similar function.

We have assumed, for simplicity, that the drum 2 turns at the s eed N of the machine 1. It can evidently be made to turn at a speed differing by any convenient ratio, as well as the drum 3.

Such a governonis suitable for all machines requiring a lngh uniformity of opera tion, especially to high frequency alternators employed in wireless telegraphy.

WVhat We claim is:

1. Electro-mechanical difi'erential governor means comprisin in combination a first organ, constant spee rotating means therefor, a second rotating organ operated by the machine to be controlled and comprisiglg,

two series of electric contacts upon whi are adapted to slide respectively two levers controlled by the constant speed organ, two electro-magnets excited by an electric source of current, the said electro-magnets act'ltlfi upon a pivoted rotor which is provided w' two reversely arranged pawls respectively engaging two toothed wheels which act in.

different direction upon the regulating organ of the machine to be controlled.

2. Device according to claim 1, in which the first organ or the organ rotating at a constant speed is constituted by a drum which is provided at its periphery with an axle upon which are mounted a pinion and a sleeve, and means to secure them, the sleeve being provided with two levers adapted to slide respectively upon the two contact series of the second organ, the said levers being connected electrically with a ring keyed upon the axis of the first drum.

3. Device according to claim 1, in which the second organ is constituted by a drum the axis of which lies in the prolongation of the first drum and comprising two series of peripheral contacts electrically connected with two rings keyed upon the axis of the said drum and a toothed wheel engaging the pinion guided by the first drum in such a manner that the speed difference between the two drums produces the rotation of the pinion of the first drum and of the sleeve and also moves the one or the other lever, according to the direction of rotation of the drums.

4. A device according to claim 1 in which the electric source for exciting the electromagnets is connected on the one hand with the ring keyed upon the axle'ot the first drum and, on the other hand, with a point common to the coils of the two electro-magnets, the free ends of each of the coils of the electro-magnets being connected with two rings keyed upon the axle of the second drum in such a manner that the one or the other of the electro-magnets is excited according to the engagement of the one or the other lever with the corresponding contacts of the second drum, and that thereby the rotating rotor of the electro-magnets, which is attracted in the one or the other direction, operates, by its pawls, the one or the other toothed wheel acting upon the regulating organ of the machine to be controlled.

-5. In combination with a constant speed revoluble element, a second revoluble element having driving means and including a drum arranged coaxially with respect to the constant speed revoluble element, said drum being provided with contacts, a gear fast with said drum, a shaft revoluble with and eccentric to said constant speed revoluble element, a sleeve loose on said shaft and having a brush for engagement with said contacts, a gear frictionally connected to said sleeve and engaging the first named gear, a translating device included in a circuit the leads of which are connected to the said contacts and said brush, speed controlling means "for the driving means of the second revoluble element, and operating means for said speed controlling means and including an element actuated by said translating device.

In testimony whereof we afiix our signatures.

ROBERT B. GOLDSOHMIDT. RAYMOND BRAILLARD. 

